Jet nozzle arrangements



Aug. 29, 1961 R. H. COLLEY 2,997,842

JET NOZZLE ARRANGEMENTS Filed Jan. 6, 1960 2 Sheets-Sheet l Inventor:

Rowan Herberf Oo//ey,

kd. (f. 6& AttorneyA.

1961 R. H. COLLEY 2,997,842

JET NOZZLE ARRANGEMENTS Filed Jan. 6, 1960 2 Sheets-Sheet 2 Inventor R0 wan HerberfCo/lg,

Gad. Cf? 5:e L Aitorney/d.

United States This invention concerns jet nozzle arrangements.

Jet nozzle arrangements are known comprising a fixed nozzle portion and a pair of substantially part-spherical, longitudinally tapering nozzle segments (known as eyelids) which are pivotally mounted outside the fixed nozzle portion so that the effective outlet area of the jet nozzle may be varied by pivotal movement of the nozzle segments. Each nozzle segment is connected by means of a linkage to a device for effecting pivotal movement of the respective nozzle segment.

It was previously considered to be essential to protect the said linkages from exposure to the hot jet gases and to this end the linkages were arranged externally of the fixed nozzle portion and were disposed within a closed annular space formed by a cylindrical sheet metal wall portion which surrounded the fixed nozzle portion.

The nozzle segments were required to seal against sealing members carried by the fixed nozzle portion and by the sheet metal wall portion in order to prevent the hot gases contacting the linkages. This arrangement was not satisfactory however, because thermal distortion of the parts made such sealing a major problem, while in order to give the nozzle segments the necessary stiffness they were usually formed in a double skin.

The present invention is based upon the discovery that, at least for certain applications, it is not essential to protect the linkages from exposure to the hot jet gases and that a more satisfactory construction for the jet nozzle arrangement may therefore be adopted.

According to the present invention, a jet nozzle arrangement comprises a fixed nozzle portion, a plurality of partspherioal, longitudinally tapering nozzle segments pivotally mounted within and closely conforming to the shape of the fixed nozzle portion so that the effective outlet area of'the jet nozzle may be varied by pivotal movement of the nozzle segments, the mounting of each nozzle segment being such as to permit a degree of free radial movement of the segment so that jet gases passing through the jet nozzle arrangement will cause the nozzle segments to be held in sealing contact with the fixed nozzle portion or with means carried thereby, and means for effecting pivotal movement of the nozzle segments.

Preferably each nozzle segment is provided with at least one radially extending slot through which passes a pivot pin carried by the fixed nozzle portion, the slot having a radial length exceeding the diameter of the pivot pin so as to permit the said degree of free radial movement.

According to a feature of the present invention each nozzle segment is fabricated of relatively light and flexible thin sheet material so as to conform to the shape of the fixed nozzle portion against which it seals.

Preferably said means for effecting pivotal movement of the nozzle segments includes linkages connected to the nozzle segments and disposed within the fixed nozzle portion so as to be exposed to jet gases passing there through.

A ram is preferably provided for effecting pivotal movement of each nozzle segment. Thus the ram may be disposed adjacent to and may extend longitudinally of the fixed nozzle portion. Alternatively the ram may be disposed adjacent to and may extend transversely of the fixed nozzle portion, the ram being connected to its re spective linkage by a bell crank lever or the like.

' atent The invention is illustrated, merely by way of example, in the accompanying drawings, in which:

FIGURE 1 is a broken away longitudinal section through a jet nozzle arrangement according to the invention,

FIGURE 2 is a rear elevation of the arrangement shown in FIGURE 1,

FIGURE 3 is a broken away longitudinal section of part of another embodiment of a jet nozzle arrangement according to the invention,

FIGURE 4 is a sectional plan view taken on the line 4-4 of FIGURE 3, and

FIGURE 5 is a rear elevation of the arrangement shown in FIGURES 3 and 4.

Referring firstly to FIGURES 1 and 2 of the drawings, the jet pipe 10 of a jet propulsion unit (not shown) is provided at its outlet end with an adjustable area discharge nozzle comprising a fixed nozzle portion 11, an end ring 12 and a pair of longitudinally tapering adjustable nozzle segments 13 mounted within the fixed nozzle portion. Each of the nozzle segments 13 is of single skin construction and is shaped internally as a half zone of a sphere. Each segment 13 is mounted at each side on a pivot pin 14 which is itself mounted in the fixed nozzle portion 11, whereby the segments 13 may swing about a diameter of the sphere for the purpose of varying the effective outlet area of the jet nozzle. In FIGURE 1 the nozzle segments 13 are shown in their minimum area positions.

The fixed nozzle portion 11, which forms a continuation of the jet pipe 10, has an enlarged diameter portion 15 at its downstream end which surrounds and extends downstream of the end ring 12. The exit end of the enlarged diameter potrion 15 is formed with an annular lip 16 which closely conforms to the shape of and forms a seal with the adjacent surfaces of the nozzle segments 13.

Each nozzle segment 13 is provided with a pair of diametrically spaced, radially elongated slots 17 through which pass the pivot pins 14. The radial length of the slots 17 is substantially greater than the diameter of the pivot pins 14 whereby each nozzle segment 13 is permitted a degree of free radial movement. The arrangement is accordingly such that the jet gases passing through the jet nozzle arrangement Will force the nozzle segments 13 radially outwardly and into contact with the lip 16, whereby to seal the segments 13 against the lip 16.

In order to assist this sealing, the nozzle segments 13 are formed of thin and flexible sheet material whose flexibility and lightness is increased by being provided with holes 18, the holes 18 being of course so disposed as to lie inwardly of the line of seal between the lip 16 and segments 13 in all pivot-a1 positions of the segments 13.

Pivotal movement of each nozzle segment 13 is effected by a double acting fluid operated ram and cylinder device whose cylinder 19 is disposed adjacent to and extends longitudinally of the fixed nozzle portion 11 and whose ram 20 is connected to the respective nozzle segment 13 by a link 21.

The ram and cylinder devices are spaced apart from each other diametrically of the fixed nozzle portion. The enlarged diameter portion 15 has integrally formed therewith a pair of diametrically spaced hollow bosses 22 through which extend the links 21.

Accordingly in this construction the links 21 will be exposed to the hot jet gases passing through the fixed nozzle portion. It has been found however, that, at least for certain applications, the links 21 can be so exposed to the hot gases and that it is therefore unnecessary to seal the space between the fixed nozzle portion 11 and the end ring 12 against the ingress of the hot gases.

In FIGURES 35 there is shown an arrangement which is broadly similar to that of FIGURES l and 2 except that, in order to fit the arrangement into a restricted nacelle space, double acting ram and cylinder devices are provided which are disposed transversely, as opposed to longitudinally, of the fixed nozzle portion. Thus each nozzle segment .13 is pivotally connected to a link 23 which is pivotally mounted on a pin 24 carried between and at one end of a pair of similar bell crank levers 25, the levers 25 being rotatably mounted on a pin 26 which itself extends between and is mounted in the respective boss 22 and end ring 12.

The bell crank levers 25 of each ram and cylinder device are connected to the ram 27 of the respective devices by way of a connecting rod 28.

If desired, the ram and cylinder devices of either FIG- URES 1 and 2 or of FIGURES 3-5 may be provided with adjustable ram stops (not shown) so that the maximum and minimum nozzle areas which are controlled by the nozzle segments may be set as required.

Each of the jet nozzle arrangements shown in the drawings as a two position arrangement, that is to say the ram and cylinder devices of each arrangement are adapted to place the nozzle segments in the maximum and minimum area positions only. If it is desired to be able to place the nozzle segments in a number of positions intermediate of the maximum and minimum area positions, this may be eflected by replacing each of the ram and cylinder devices by a sleeve which is mounted for axial movement only and which is connected to a link 21 or 23, the sleeve being internally threaded and receiving an externally threaded shaft which is mounted for rotation only. The two externally threaded shafts may be rotated by a common, air operated, motor.

I claim:

1. A jet nozzle arrangement comprising a fixed nozzle portion, a plurality of arcuate, longitudinally tapering nozzle segments of flexible sheet material pivotally movable within and closely conforming to the shape of the fixed nozzle portion, each said nozzle segment being provided with a pair of radially extending slots, pivot pins mounted in said fixed nozzle portion and extending through said slots, the slots having a radial length exceeding the diameter of the pivot pins so that jet gases passing through the jet nozzle arrangement will deflect the nozzle segments radially outwardly into sealing contact with the fixed nozzle portion, and means for effecting pivotal movement of the nozzle segments whereby to vary the efiective outlet area of the jet nozzle.

2. A jet nozzle arrangement comprising a fixed nozzle portion, a plurality of arcuate, longitudinally tapering nozzle segments of flexible sheet material pivotally movable within and closely conforming to the shape of the fixed nozzle portion, mounting means for mounting each nozzle segment within the fixed nozzle portion, said mounting means being constructed to permit a degree of free outward radial movement of the segment so that jet gases passing through the jet nozzle arrangement will deflect the nozzle segments outwardly into sealing contact with the fixed nozzle portion, and means for effecting pivotal movement of the nozzle segments whereby to vary the elfective outlet area of the jet nozzle.

3. A jet nozzle arrangement comprising a fixed nozzle portion, a plurality of arcuate, longitudinally tapering nozzle segments of flexible sheet material pivotally movable within and closely conforming to the shape of the fixed nozzle portion, mounting means for mounting each nozzle segment within the fixed nozzle portion, said mounting means being constructed to permit a degree of free outward radial movement of the segment toward the fixed nozzle portion so that jet gases passing through the jet nozzle arrangement will deflect the nozzle segments into sealing contact with the fixed nozzle portion, and means including linkages connected to the nozzle segments for eifecting pivotal movement of the nozzle segments whereby to vary the effective outlet area of the jet nozzle, said linkages being disposed within the fixed nozzle portion and being exposed to the jet gases passing therethrough.

4. A jet nozzle arrangement comprising a fixed nozzle portion, a plurality of arcuate, longitudinally tapering nozzle segments of flexible sheet material pivotally movable within and closely conforming to the shape of the fixed nozzle portion, mounting means for mounting each nozzle segment Within the fixed nozzle portion, said mounting means permitting a degree of free outward radial movement of the segment toward the fixed nozzle portion so that jet gases passing through the jet nozzle arrangement will deflect the nozzle segments into sealing contact with the fixed nozzle portion, a ram for effecting pivotal movement of the nozzle segments whereby to vary the effective outlet area of the jet nozzle, and linkages interconnecting said ram with said nozzle segments, said linkages being disposed within the fixed nozzle portion and being exposed to the jet gases passing therethrough.

5. A jet nozzle arrangement as claimed in claim 4 in which the ram is disposed adjacent to and extends longitudinally of the fixed nozzle portion.

6. A jet nozzle arrangement as claimed in claim 4 in which the ram is disposed adjacent to and extends transversely of the fixed nozzle portion, the ram being connected to its respective linkage by a bell crank lever.

References Cited in the file of this patent UNITED STATES PATENTS 2,667,226 Doblhoff Ian. 26, 1954 2,738,644 Alford Mar. 20, 1956 2,840,985 Elliott July 1, 1958 

